Converter and gears

Good luck with what ever you do..............however I am some what mystified; after putting a combination like this and it looks stout; that you are clueless as to what would be appropriate for converter and gear

I'm dumber than a box of rocks...........I'll say 3.90's and 4500 rpm
Ya kinda funny I'd admit. Last car was a twin turbo with twice the hp as this one and ran 142mph in the 1/8. This car now is more than half the budget and a big block mopar and also lighter than my last one. Most likely it's only going to be 700hp if I'm lucky so need it to more out